The present invention relates to a variable-capacity store for objects.
More specifically, the present invention relates to a variable-capacity store for objects defined, for example, by elongated elements, and of the type comprising an input station and an output station located in series along a feed path of the elongated elements; an endless conveyor comprising a conveying branch, for feeding said elongated elements along said path, and a return branch, which respectively form a first and a second spiral of given lengths about respective pairs of guide drums; and adjusting means for adjusting said lengths in complementary manner; said pairs of drums each comprising a fixed first drum, and a second drum movable to and from the relative first drum; and said second drums being located on the same side with respect to the relative first drums.
The present invention may be used to advantage for storing cigarettes, to which the following description refers purely by way of example.
For storing cigarettes, a store of the type defined above, and as described for example in EP 0738478, is interposed between a cigarette manufacturing machine and a packing machine to compensate for any difference between the number of cigarettes produced and the number of cigarettes packed, by lengthening or shortening the first or conveying spiral, and by shortening or lengthening the second or return spiral in complementary manner.
To move one of the two movable drums away from the relative fixed drum and move the other movable drum towards the relative fixed drum in complementary manner, known stores of the above type normally employ two independent reversible motors controlled by a single central control unit sensitive to any difference between the number of cigarettes produced and the number packed.
In known stores of the above type, the two motors, which must be operated simultaneously and in relation to each other, may give rise to both functional and mechanical problems, and in any case involve relatively high production and maintenance costs.
It is an object of the present invention to provide a store of the above type, designed to eliminate the aforementioned drawbacks.
According to the present invention, there is provided a variable-capacity store for objects, the store comprising an input station and an output station located in series along a feed path of the objects; an endless conveyor comprising a conveying branch, for feeding said objects along said path, and a return branch, which respectively form a first and a second spiral of given lengths about respective pairs of guide drums; and adjusting means for adjusting said lengths in complementary manner; said pairs of drums each comprising a fixed first drum, and a second drum movable to and from the relative first drum; said second drums being located on the same side with respect to the relative first drums; and the store being characterized in that said adjusting means comprise a transmission connecting said second drums and for moving the second drums equally and oppositely with respect to the relative first drums; and a reversible motor for powering said transmission.